Modern medical apparatuses are often controlled by a microprocessor that, for example, operates pumps, reads sensors and communicates with an operator via a user interface like a monitor, keypad and/or touchscreen. This user interface can make use of text, pictograms and/or graphical icons to guide an operator through the setup and give him/her necessary information during a therapy that is performed by the medical apparatus. Thereby, parameter input is an essential part of such medical equipment.
For example, extracorporeal blood treatment (ECB) involves the continuous withdrawal of blood from a patient, where the blood is processed within a medical device outside of the patient and is then returned to the patient. Thereby, parameters like the ultrafiltration volume, the therapy time and the ultrafiltration rate can be input by a nurse depending on the patient′ prescription, and the medical apparatus can then individually perform the therapy for each patient. The traditional way is the separate input of parameters, i.e. one by one entering the values by any means. However, some of such parameters are mutually dependent from each other and possibly from even the time passed during the therapy, which can cause usability problems.
The main disadvantage of this traditional way of parameter entering is the frequent need of several iterative inputs of such dependent parameters, which basically means a poor usability. First of all, it wastes time to enter and confirm the later possibly improper parameter value. Furthermore, the explanatory power why a desired value of a parameter cannot be entered or what value is possible to be entered is poor.